function B(){
	this.name = '王娇';
	this.age = '18';
}
B.prototype.sayHello = function(){
	console.log("真奇怪！！！");
}
function A(){
	this.title = '牛魔王';
}
// A继承B
A.prototype = new B();
// 问题1: 是A.constructor === B.constructor;
// console.log(A.constructor === B.constructor);
// 修正指向问题
A.prototype.constructor = A;

var person = new A();
console.log(person.name);
console.log(person.title);
person.sayHello();